This invention relates to processes for producing a turbine or compressor bucket, or blade, having a plurality of passages therein relatively close to the surface of the bucket for the passage of liquid therethrough in order to cool the bucket during operation.
One such process is described in U.S. Pat. application Ser. No. 749,719--Anderson, filed Dec. 13, 1976, and assigned to the assignee of the instant invention.
The Anderson application discloses a liquid-cooled gas turbine bucket comprised of a core having radially extending grooves of rectangular cross-section recessed into the core, tubing fitted into these grooves and bonded in place by means of braze material filling in the space between the tubes and the sides and bottom of the grooves, and a protective skin bonded to the outer surface of the core to provide corrosion resistance. The skin is described as a composite of an inner skin which provides high thermal conductivity and an outer skin which provides protection from hot corrosion. However, there is no disclosure of any performing of the composite skin or any attempt to optimize the bond between the inner and outer skin materials.
The disclosure in the Anderson application of useful materials for preparation of the outer skin, the inner skin, the tubing and the bucket core is incorporated by reference.
The general method of incorporating an assembly to be brazed in a flexible envelope for the establishment within the envelope of a substantially non-oxidizing atmosphere and providing for force application to the envelope during brazing is disclosed in U.S. Pat. No. 3,091,846--Henry. The disclosure therein is incorporated by reference.